Effects of radiotherapy on men

Radiotherapy can cause side effects that may affect your sex life. It may cause skin reactions. The treatment area can become sore and itchy, which can make sex difficult. This can also affect the way you feel about how you look.

Radiotherapy can also cause extreme tiredness. This can go on for weeks or months. You may find you’re too tired to have sex.

Radiotherapy specifically to the pelvic area (the prostate, anus, rectum or bladder) may cause other side effects. These may include:

  • diarrhoea and feeling sick (nausea)
  • pain or bleeding in the bladder or rectum
  • difficulty having an erection
  • ejaculation problems
  • difficulty passing urine.

Most of these side effects are temporary and there are ways to manage them. After pelvic radiotherapy, many men have erection difficulties. Talk to your nurse specialist about this. They may be able to suggest treatments that could help.

Radiotherapy and sexuality

Radiotherapy treats cancer by using high-energy rays that destroy the cancer cells, while doing as little harm as possible to normal cells. It can either be given as external radiotherapy from outside the body using x-rays, or from within the body as internal radiotherapy.

Usually there’s no medical reason to stop having sex during external radiotherapy. If you’re having internal radiotherapy, you will have to talk to your doctor or specialist nurse about how it will affect your sex life.

Skin reaction

Radiotherapy can cause a skin reaction. How your skin reacts will depend on the amount of radiotherapy you have. You may find that the skin in the treatment area becomes red and sore or itchy. The skin in the groin, perineum and anal areas can be very sensitive. If a skin reaction does occur, it can make sex difficult.

A possible long-term side effect of radiotherapy is damage to the tiny blood vessels close to the surface of the skin. This will cause red spidery marks on the skin and is called telangiectasia. These blood vessels can be delicate and are more likely to bleed. Telangiectasia may affect how you feel about the way you look, or make sexual contact difficult if your skin is fragile.


Radiotherapy can cause fatigue (tiredness that doesn’t go away with rest). This can last for several weeks or months.

Sex may be one of the last things on your mind, or you may just be too tired to have sex.

Radiotherapy to the pelvic area

Radiotherapy may be given to the pelvic area to treat cancers of the prostate, anus, rectum and bladder. Having radiotherapy to the pelvic area can affect the way you have sex. This can be more of a problem if you’ve also had surgery to your pelvic area.

Pelvic radiotherapy can cause side effects such as diarrhoea and nausea (feeling sick). You may get inflammation of the bladder (cystitis) or rectum, which can cause pain and bleeding. These side effects can either make sex difficult or affect your desire to have sex. Most of these side effects are temporary, but very rarely they can be permanent.

We have more information about the possible side effects of pelvic radiotherapy.

Erectile dysfunction (ED)

Radiotherapy to the pelvic area can reduce your ability to have an erection. Up to 70% of men (7 in 10) have problems getting or keeping an erection after radiotherapy for prostate cancer. If you are affected, you may find your erections aren’t as strong as they were before the treatment, and that this gradually gets worse over a year or two.

ED happens because the blood vessels that supply blood to the penis become scarred and can’t let enough blood through to fill the penis. You may get an erection but then lose it, or you may be unable to have an erection at all.

There are treatments that, if started soon after radiotherapy, may help prevent erectile difficulties in some men.

Ejaculation problems

If you can still have and keep erections after pelvic radiotherapy, it’s very common to have dry orgasms. When this happens, little or no semen is ejaculated at orgasm. This is not harmful but can worry you if you don’t expect it.

Some men feel a sharp pain as they ejaculate if they have recently had radiotherapy treatment. This is caused by radiation irritating the urethra. This problem usually disappears within a few weeks once treatment has ended.

Urinary problems

If you have internal radiotherapy (brachytherapy) for prostate cancer, you may develop problems passing urine. You may need a tube into the bladder to drain urine (a catheter), or you may have leakage of urine (incontinence). Often these problems are temporary, but sometimes they may be permanent.

Hormonal changes

Occasionally men who have had pelvic radiotherapy produce less testosterone, which is important for sex drive.

Back to Effects of treatment on a man's sexuality

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